1. Field of the Invention
The invention relates to a device for selecting values of data elements forming part of a group of various types of data elements, the device comprising an operation means, display means and first register means for registering and delivering values of data elements to said display means; the operation means, dependent upon the time said means is operated, causing the selection of a value of a data element. Said group of data elements may comprise data elements such as digit elements for the ones, for the tens, for the hundreds etc, with which decimal values of parameters can be denoted and selected. Furthermore also other data elements are possible such as a function notation, in which case out of a number of different functions one function (i.e. the "value" of the function data element) can be selected, or a command, the values of which can for example be "go" or "no go" respectively.
2. Description of the Prior Art
Such devices in which the operation means is commonly formed by a key or switch, are known in the art. For example in channel selection devices for television apparatus it is known to have only one key by which, dependent upon the time said key is pressed, a certain channel number representing the value of this data element "channel" is selectable. Also in other types of apparatus, this type of input selection device is known, for example for ovens used as household appliances. In such appliances, for example, a temperature has to be selected from a complete temperature range. In the known device this is realized by an up/down key device, having an up-key and a down-key by which the values of the subsequent temperatures pass over a display means. Hereby there is no distinction between data elements "ones" and "tens" and "hundreds", rather the temperatures are presented as complete figures as, for example, 80, 85 , . . . 100, 110, 120, . . . . Thus there is no separate selection of the first decimal, the second decimal etc. but there is only one data element "temperature". In the known apparatus to be able to select more than one data element it is necessary to have more keys, that is to say one key for each distinguished data element, the value of which has to be selectable separately. In these days in which the possibilities of handling great numbers of different data elements are increasing due to the fact that new developments in the field of electronics, as for example the microprocessor on one chip etc, create the circumstances therefor, it becomes a problem to be able to select all the values of these data elements. Straight forward there is no principal problem: just using more keys to be able to select the values in connection with the relevant data elements. Practically however there are boundaries such as costs, space on the control panel of the apparatus, reliability as to the safeguarding that all keys will operate without trouble for a long time. In this respect there are reasons to find out whether there is a solution for having a minimum number of keys with which a maximum of data elements, the value of which are to be selected, can be handled.